The present invention relates to proteins derived from Lawsonia intracellularis and encompasses related proteins, nucleic acids, and immunogenic compositions. The immunogenic compositions are particularly useful in prevention of L. intracellularis infections in susceptible animals, such as pigs. The proteins, fragments, and nucleic acids can also be employed as diagnostic agents.
Commercially raised pigs are sensitive to a wide spectrum of intestinal diseases or syndromes that are collectively referred to as porcine proliferative enteropathy (PPE). These diseases include intestinal adenomatosis complex (Barker I. K. et al., 1985, In xe2x80x9cPathology of Domestic Animals,xe2x80x9d 3rd Edition, Vol. 2 p. 1-237, eds. K, V. F. Jubb et al. (Academic Press Orlando)), porcine intestinal adenomatosis (PIA), necrotic enteritis (Rowland A. C. et al., 1976, Veterinary Record 97:-178-180), proliferative haemorrhagic enteropathy (Love, R. J. et al., 1977, Veterinary Record 100: 473), regional ileitis (Jonsson, L. et al., 1976, Acta Veterinaria Scandinavica 17: 223-232), haemorrhagic bowel syndrome (O""Neil, I. P. A., 1970, Veterinary Record 87:742-747), porcine proliferative enteritis and Campylobacter spp-induced enteritis (Straw, B. E., 1990, Journal of American Veterinary Medical Association 197: 355-357).
One major type of PPE is non-haemorrhagic and is manifested by porcine intestinal adenomatosis (PIA). This form of PPE frequently causes growth retardation and mild diarrhea. Another important type of PPE is haemorrhagic. It is often fatal, and is manifested by proliferative haemorrhagic enteropathy (PHE) wherein the distal small intestine lumen becomes engorged with blood.
While PPE in pigs is commercially most important, PPE is also a problem in the raising of hamsters (Stills, H. F., 1991, Infection and Immunology 59: 3227-3236), ferrets (Fox et al. 1989, Veterinary Pathology 26: 515-517), guinea pigs (Elwell et al., 1981, Veterinary Pathology 18: 136-139), rabbits (Schodeb et al., 1990, Veterinary Pathology 27: 73-80) and certain birds (Mason et al, 1998).
The organism that causes PPE is the Campylobacter-like bacterium xe2x80x9cL. intracellularisxe2x80x9d (McOrist S et al, 1995, International Journal Of Systematic Bacteriology 45: 820-825). This organism is also known as lleal symbiont intracellularis (Stills, 1991, supra). PPE-like diseases in pigs may also be caused by other species of Campylobacter (Gebhart et al., 1983, American Journal of Veterinary Research 44: 361-367).
L. intracellularis is located in the cytoplasm of villi and intestinal crypt cells of infected animals, where it causes structural irregularities and enterocyte proliferation. Abscesses form as the villi and intestinal crypts become branched and fill with inflammatory cells.
Current control of PPE relies on the use of antibacterial compounds. There is, however, a need for alternative means of controlling L. intracellularis infection.
International Patent Application No. PCT/AU96/00767 describes L. intracellularis polypeptides and immunogenic compositions that are useful as vaccines. There is, however, a need for additional compositions that confer resistance to L. intracellularis infection.
The present invention relates to an isolated polynucleotide molecule comprising a nucleotide sequence that is selected from the group consisting of:
a) a nucleotide sequence encoding L. intracellularis HtrA, PonA, HypC, LysS, YcfW, ABC1, or Omp100 protein;
b) a nucleotide sequence that is a substantial part of the nucleotide sequence encoding the L. intracellularis HtrA, PonA, HypC, LysS, YcfW, ABC1, or Omp100 protein; and
c) a nucleotide sequence that is homologous to the nucleotide sequence of a) or b).
In another aspect, the invention relates to a recombinant vector comprising these polynucleotide molecules, including those encoding a carrier or fusion partner such that expression of the recombinant vector results in a fusion protein comprising the carrier or fusion partner fused to a protein or polypeptide encoded by the nucleotide sequences described above. The invention also encompasses transformed host cells comprising these recombinant vectors and polypeptides produced by such transformed host cells.
In another aspect, the present invention relates to an isolated polypeptide that is selected from the group consisting of:
(a) L. intracellularis HtrA, PonA, HypC, LysS, YcfW, ABC1, or Omp100 protein;
(b) a polypeptide having an amino acid sequence that is homologous to that of the L. intracellularis HtrA, PonA, HypC, LysS, YcfW, ABC1, or Omp100 protein;
(c) a polypeptide consisting of a substantial portion of the L. intracellularis HtrA, PonA, HypC, LysS, YcfW, ABC1, or Omp100 protein or of the polypeptide having an amino acid sequence that is homologous to that of the L. intracellularis HtrA, PonA, HypC, LysS, YcfW, ABC1, or Omp100 protein;
(d) a fusion protein comprising the protein or polypeptide of (a), (b) or (c) fused to another protein or polypeptide; and
(e) an analog or derivative of the protein or polypeptide of (a), (b), (c) or (d).
The present invention further provides a polynucleotide molecule comprising a nucleotide sequence of greater than 20 nucleotides having promoter activity and found within SEQ ID NO: 2 from about nt 2691 to about nt 2890.
The present invention further relates to a method of preparing any of these polypeptides, comprising culturing host cells transformed with a recombinant expression vector and recovering the expressed polypeptide from the cell culture. The vector comprises a polynucleotide molecule comprising a nucleotide sequence encoding any of the polypeptides, the nucleotide sequence being in operative association with one or more regulatory elements. Culturing is conducted under conditions conducive to expression of the polypeptide.
In yet another aspect, the invention relates to an isolated antibody that specifically reacts with any of the L. intracellularis HtrA, PonA, HypC, LysS, YcfW, ABC1, or Omp100 proteins or polypeptides described above.
The invention also relates to an immunizing composition that comprises an immunologically effective amount of a protein, polypeptide, antibody, or polynucleotide of the invention in combination with a pharmaceutically acceptable carrier. The present invention encompasses a method of immunizing a PPE susceptible animal against L. intracellularis infection that comprises administering to the animal the immunizing composition.
The invention also relates to a kit for immunizing a PPE susceptible animal against a disease condition caused or exacerbated by L. intracellularis that comprises a container having therein an immunologically effective amount of one of the proteins, polypeptides, antibodies, or polynucleotides described above. The invention also relates to a kit for detecting the presence of L. intracellularis, an L. intracellularis specific amino acid or nucleotide sequence, or an anti- L. intracellularis antibody, comprising a container that has therein a protein, polypeptide, polynucleotide, or antibody of the invention.